Reading File
Finding Sources
Finding Sources
Reading File
Finding Sources
The textbook sources confirm the answer. Here is the full breakdown:
Answer: (c) 1, 3 and 4
Let's analyze each statement:
Statement 1 - CORRECT: Serum calcium levels improve earlier than serum PTH levels
Per Harrison's Principles of Internal Medicine 22E, when vitamin D deficiency is treated:
"Normocalcemia is usually observed within 1 week of the institution of therapy, although increases in PTH and alkaline phosphatase levels may persist for 3-6 months."
So calcium normalizes quickly, while PTH takes much longer to return to normal. Statement 1 is true.
Statement 2 - INCORRECT: Vitamin D toxicity occurs "frequently"
Harrison's explicitly states:
"The safety margin for vitamin D is large, and vitamin D toxicity usually is observed only in patients taking doses in the range of 40,000 IU daily."
Vitamin D toxicity is rare, not frequent. Routine serial monitoring for toxicity is not routinely required for standard supplement doses. Statement 2 is false.
Statement 3 - CORRECT: Vitamin D supplementation should always be in conjunction with calcium supplementation
Harrison's states directly:
"Vitamin D should always be repleted in conjunction with calcium supplementation since most of the consequences of vitamin D deficiency are a result of impaired mineral ion homeostasis."
Statement 3 is true.
Statement 4 - CORRECT: Nephrolithiasis is a known complication
Harrison's notes:
"Levels >250 mg/24 h [urinary calcium] predispose to nephrolithiasis and should lead to a reduction in vitamin D dosage and/or calcium supplementation."
Fitzpatrick's Dermatology similarly confirms that excess vitamin D can lead to kidney stones. Statement 4 is true.
Summary
| Statement | Verdict |
|---|---|
| 1. Calcium improves before PTH | TRUE |
| 2. Toxicity occurs frequently | FALSE |
| 3. Always combine with calcium | TRUE |
| 4. Nephrolithiasis is a known complication | TRUE |
Correct answer: (c) 1, 3 and 4
- Harrison's Principles of Internal Medicine 22E, Vitamin D Deficiency section (lines 897-899)
- Fitzpatrick's Dermatology, Functions of Vitamin D section
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